WASHINGTON (Reuters) - Barack Obama easily won three more Democratic nominating contests on Tuesday, extending his winning streak over rival Hillary Clinton and building momentum in a hard-fought U.S. presidential race.
Obama rolled to decisive victories in Virginia, Maryland and the District of Columbia, running his hot streak to eight consecutive wins and expanding his lead in pledged convention delegates who select the party's nominee.
Republican front-runner John McCain defeated his last major challenger, former Arkansas Gov. Mike Huckabee, in Virginia, Maryland and the District of Columbia as he moved closer to clinching the party's nomination for the November election.
The wins for Obama, who would be the first black U.S. president, followed big weekend triumphs in Maine, Louisiana, Nebraska, Washington and the Virgin Islands.
All three of Tuesday's contests occurred in fertile territory for Obama, with large populations of the highly educated, high-income and black voters who have favored the Illinois senator.
But exit polls indicated Obama cut dramatically into Clinton's core support groups. He led among women, Hispanics and lower-income voters in Virginia and essentially split the votes of whites with Clinton. In Maryland, he captured seniors above the age of 65 and rural voters.
In Virginia, Obama was winning more than 60 percent of the vote with more than two-thirds of the precincts reporting.
Obama already had edged past Clinton in the race for pledged delegates who formally select a party nominee at a convention in August. A total of 168 Democratic delegates were at stake in Tuesday's voting.
Obama had 958 pledged delegates to Clinton's 904, according to a count by MSNBC before Tuesday's voting -- well short of the 2,025 needed to clinch the Democratic nomination.
(Additional reporting by Deborah Charles, Jeff Mason, Andrew Stern, Caren Bohan; Editing by Lori Santos)
(To read more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at http://blogs.reuters.com/trail08/)
